Nice.  Thanks.

BTW, I know what fmt is, but what do a- and a+ do?

On 11/13/2012 3:13 PM, Jacek Masiulaniec jacekm-at-dobremiasto.net
|9fans| wrote:
> My latest addition to the acme column tag, alongside |a-, |a+, and |fmt.
>
> #!/usr/bin/env rc
>
> fn f {
> n=$1
> if(! cat $f | cut -c1-$n | 9 grep -v '^[ ]+$' >/dev/null){
> x=`{f `{expr $n + 1}}
> echo '.'$"x
> }
> }
>
> f=/tmp/com.$pid
> cat >$f
>
> switch($%){
> case *.go *.c
> c='//'
> case *
> c='#'
> }
>
> # Remove comment?
> if(cat $f | 9 grep '^[ ]*'$c' ' >/dev/null){
> cat $f | 9 sed 's|'$c' ||'
> rm $f
> exit
> }
>
> # Add comment.
> s=`{f 1}
> if(~ $#s 0)
> cat $f | 9 sed 's|^|'$c' |'
> if not
> cat $f | 9 sed 's|^('$"s')|\1'$c' |'
>
> rm $f
>
> I name this |com. The original motivation was to avoid manual keying
> in of the comment characters, which I found myself doing quite
> frequently for short line ranges.
>
> It also works well with Go's "imported and not used" error. Once
> plumbed to the offending import line, it only takes one click to
> temporarily disable an import.